An evaporator used as a part of a refrigeration cycle in an air conditioning apparatus evaporates a liquid phase refrigerant inside the air conditioning apparatus to lower a temperature of the refrigerant, and thereby cools the air by heat exchange with the refrigerant.
In the air conditioning apparatus for a vehicle, a compressor is operated by a driving force of an internal combustion engine, and thereby circulates the refrigerant. For that reason, since the circulation of the refrigerant is stopped in a state where the internal combustion engine is stopped, the air passing through the evaporator cannot be cooled.
In recent years, vehicles that perform so-called idle stop, in which the internal combustion engine is automatically stopped at the time of temporary stop, are in widespread use. In such a vehicle, the internal combustion engine stops relatively frequently during operation, and the compressor stops each time. At that time, when the air is no longer cooled as described above, a temperature in a vehicle interior rises and an occupant feels uncomfortable.
Therefore, an evaporator having a cold storage mechanism has been proposed and already put to practical use (refer to, for example, Patent Literature 1 below). The cold storage mechanism is a mechanism, in which a cold storage material such as paraffin is housed inside a container, and is disposed in contact with a tube or the like of the evaporator through which the refrigerant passes.
When the compressor is operating by the driving force of the internal combustion engine, the cold storage mechanism (cold storage container) is cooled by heat exchange with the refrigerant which has become low temperature in the evaporator, and the cold storage material housed in the cold storage container is solidified.
Thereafter, even if the idle stop is performed and the circulation of the refrigerant is stopped, the cold storage mechanism and the tube disposed in the vicinity of the cold storage mechanism are maintained at a low temperature by the solidified cold storage material. For that reason, the air blown into the vehicle interior through the evaporator can be continuously cooled for a while.